Specificity of the Toxic Factors Associated with the Epidemic and the Murine Strains of Typhus Rickettsiae 1

Abstract

Immunological studies on epidemic and murine strains of the rickettsiae of typhus fever, carried on over a period of years, have shown that the two agents are closely related, in that animals which recover from infection with one strain are immune to the other (1). However, Plotz (2) has shown that the complement-fixing antibodies produced by the two types of rickettsiae are highly specific when purified rickettsiae are used as antigens. A new method of investigating the specificity of typhus strains was afforded by the observations of Gildemeister and Haagen (3) that a “toxin” is associated with living murine rickettsiae and that this “toxin” could be neutralized by sera from convalescent epidemic and endemic human cases. Bengtson, Topping, and Henderson (4), and Henderson and Topping (5), greatly extended the work on this toxic factor.